1. Field of the Invention
This invention generally relates to upright-type keyboard instruments such as upright pianos, electronic pianos, sound-mute-type pianos, automatic performance pianos (or player pianos), and in particular to pedal mechanisms adapted thereto.
This application claims priority on Japanese Patent Application No. 2002-340104, the content of which is incorporated herein by reference.
2. Description of the Related Art
Conventionally, keyboard instruments such as grand pianos, upright pianos, and other automatic performance pianos (or player pianos) incorporating automatic performance mechanisms are equipped with-pedal mechanisms such as muting (or sound-softening) mechanisms, muffler mechanisms, and damper mechanisms (or loud mechanisms), for example.
In the case of an upright piano shown in FIG. 5, a piano housing 100 has a keybed 101 arranged approximately at the center position thereof, on which keys are arranged in a keyboard 10 and are respectively operated to activate actions (or action mechanisms), wherein numerous strings are stretched under tension in a frame that is vertically arranged in the piano housing 100. Upon depression of each key 10, the action is activated to rotatably move a hammer to strike the corresponding string(s), thus producing a sound.
Specifically, the piano housing 100 comprises left/right side boards 102, a lower bottom sill 103, left/right toe blocks 104, a pair of legs 105 for supporting the keybed 101 on the toe blocks 104, a lower front board 106, an upper front board 107, a top board 108, a pair of left/right side arms 109, support poles (not shown) arranged in the rear side thereof, and a fall board 110 that is opened or closed on the keyboard 10.
Three pedals are arranged to be projected forward from the center portion of the bottom sill 103, wherein there are provided a soft pedal 25, a muffler pedal 26, and a damper pedal (or a loud pedal) 27.
An example of the conventional pedal mechanism adapted to the aforementioned upright piano is disclosed in Japanese Patent Application Publication No. 2001-312269, which corresponds to U.S. Pat. No. 6,448,481.
A muting mechanism is designed to move a hammer rail towards strings upon depression of a soft pedal so that the distance between the hammer and the string is reduced to weaken the striking force of the hammer, thus reducing the sound.
A muffler mechanism 36 (see FIG. 6) is designed to intervene a muffler felt between the action and the string upon depression of the muffler pedal 26, so that the hammer strikes the string via the muffler felt so as to weaken the sound.
A damper mechanism is designed to press the string with a damper so as to temporarily stop sound generation, wherein it is interlocked with the keyboard or the damper pedal during the performance of a piano so as to release the damper from pressing the string as necessary. Specifically, when the damper mechanism is interlocked with the keyboard only, a damper corresponding to the ‘depressed’ key is only being activated. When the damper mechanism is interlocked with the damper pedal only, all of dampers are collectively activated to simultaneously release all strings therefrom.
In order to activate the pedals arranged on the lower bottom sill 103, for example, the piano housing 100 is equipped with a pedal link mechanism including pedal levers.
As shown in FIG. 6, movements of the soft pedal 25 and the damper pedal 27 are respectively transmitted to vertical links 31 and 32 via pedal levers 29 and 30, which are arranged on a base board 28, so that a muting mechanism or a damper mechanism arranged in connection with an action (not shown) is activated.
The movement of the muffler pedal 26 is transmitted to the muffler mechanism 36 arranged in connection with the action via a muffler link 33, a link 34, and an interconnection link 35.
The center portions of the pedal levers 29 and 30 are pivotally supported by the base board 28 by bearing members 37 and are normally pressed in restoration directions by compression coil springs 38.
In the conventional pedal link mechanism adapted to the upright piano described above, the pedal levers 29 and 30 are individually fixed onto the upper surface of the base board 28 via the bearing members 37, wherein the compression coil springs 38 are arranged between the pedal levers 29 and 30, and the base board 28. This takes a relatively long time to fix the aforementioned members because of the complicated and troublesome assembling work in manufacture.
In order to eliminate the aforementioned drawback, Japanese Patent Application Publication No. 2001-312269 discloses a base board unit in which pivotally moving members and their bearings for pedal levers, which are pivotally moved by pedals, are combined together and are fixed to the base board or keybed of the piano housing.
The aforementioned constitution may improve the workability in fixing the pedal link mechanism that interconnects together various pedals and their operating mechanisms. However, in order to fix the base board unit including the pedal levers onto the base board of the piano housing, it is necessary to realize a sufficiently high rigidity in the base board, which in turn requires a ‘rigid’ bottom sill. In the case of an automatic performance piano and an electronic piano, it is necessary to provide a prescribed space for the installation of electric components such as a power source unit, an electronic sound source, and an amplifier. However, the conventional upright piano cannot provide a sufficiently large space for the installation of electric components on the base board thereof, whereby numerous components should be arranged in a relatively small space. This may cause mutual interference between electrical components and other parts, and this may also prevent heat generated by electrical components from being radiated or dissipated.
The aforementioned problem could be eliminated by fixing the base board unit including pedal levers onto the keybed, whereas the keybed is reduced in strength so as to cause a unwanted reduction of durability. As long as the pedal levers are incorporated into the base board unit, there occurs similar problems in fixing the base board unit to any position of the piano housing. In addition, there occur other problems due to restrictions regarding the freedom of design and actual operations with regard to arranging positions of bearings, restoration springs, and the like.